Depression in mothers parenting young children is common and undertreated. Depression is debilitating for mothers, negatively affects their parenting, and is associated with mental, behavioral, and physical health problems in their children. Identifying and treating mothers with depression improves both the mothers' well-being and their children's mental and overall health. Pediatric visits offer a potential significant opportunity to intervene. Mothers may see their child's pediatric provider more often than their own, and these providers could motivate mothers to seek effective, underutilized, formal depression care, by communicating how recovery from depression is linked to child well-being. Therefore, in recent pilot work, we developed a pediatric setting-based intervention that includes a validated maternal depression screen, and subsequent depression education and care-seeking motivational messages that emphasize the benefits of maternal depression care for children. Initial testing demonstrated that depression screen-positive mothers receiving the intervention had greater intention and attempts to seek depression care compared to mothers receiving usual care. [We then professionally translated the intervention into Spanish as a first step in increasing the generalizability of the intervention through refinement in future studies.] As is often the case with interventions tested as a package, we lack empirical evidence on which components of the pilot intervention deliver the greatest effects. Therefore, we propose to adopt a rapid-cycle intervention improvement approach. We will: (1) refine the components of the pilot-tested intervention [and a Spanish-language translation] using qualitative data and (2) assess the effects of those proposed refinements on depression screen-positive mothers' depression care- seeking, using factorial experiments. The resulting intervention will be provisionally optimized by including only those refined components found to be most experimentally efficacious. This provisionally optimized intervention will have a higher probabilit of demonstrating reproducible effectiveness, potentially speeding the way to implementation. [The ultimate optimized intervention will improve maternal depression care by being an essential link in future integrated systems between pediatric-based maternal depression screening and effective community-based programs for maternal mental health care.] My long-term career goal is to become a national leader in improving intergenerational mental health, particularly for patients in disadvantaged settings, by developing interventions for pediatric providers to guide parents to effective, [integrated] mental and behavioral health care for themselves and their children. My medium-term career goal is to develop pediatric-based interventions for improving access to and uptake of effective but underused maternal depression therapies. My short-term career goals are to acquire expertise in maternal depression [affecting diverse populations] and in care-seeking intervention optimization strategies, and to advance the field by (1) better understanding mothers' preferences for pediatric-based maternal depression interventions and (2) producing a provisionally optimized pediatric-based intervention to increase maternal depression care-seeking. These goals will be achieved through further training and mentoring in (1) qualitative research design, implementation, and analysis; (2) design and analysis of data from adaptive and factorial randomized-controlled trials used in the optimization of interventions with multiple components; (3) [community-based, culturally appropriate] maternal mental health services [and research]; and (4) institutional and national career progression as a pediatrician-researcher. The proposed research will be conducted at the University of California, Davis (UCD). The research and training environment at UCD supporting the proposed work includes: the Department of Pediatrics and its associated multiple pediatric clinic sites; the NIH Clinical and Translational Science Center; [the Center for Reducing Health Disparities;] the Center for Healthcare Policy and Research; graduate level courses in qualitative research, grant writing, health informatics, and career development as a clinician-researcher; infrastructure for database management and statistical planning and analysis; a training program in the responsible conduct of research; and an emphasis on experienced researchers mentoring junior faculty, both interdepartmentally and within the Department of Pediatrics. UCD has a long history of collaborative research and training directly relevant to the aims of this Career Development Award.